Identification and Functional Characterization of Abiotic Stress Tolerance-Related PLATZ Transcription Factor Family in Barley (Hordeum vulgare L.)

Plant AT-rich sequence and zinc-binding proteins (PLATZs) are a novel category of plant-specific transcription factors involved in growth, development, and abiotic stress responses. However, the <i>PLATZ</i> gene family has not been identified in barley. In this study, a total of 11 <i>HvPLATZs</i> were identified in barley, and they were unevenly distributed on five of the seven chromosomes. The phylogenetic tree, incorporating PLATZs from <i>Arabidopsis</i>, rice, maize, wheat, and barley, could be classified into six clusters, in which HvPLATZs are absent in Cluster VI. <i>HvPLATZs</i> exhibited conserved motif arrangements with a characteristic PLATZ domain. Two segmental duplication events were observed among <i>HvPLATZs</i>. All <i>HvPLATZs</i> were core genes present in 20 genotypes of the barley pan-genome. The <i>HvPLATZ5</i> coding sequences were conserved among 20 barley genotypes, whereas <i>HvPLATZ4/9/10</i> exhibited synonymous single nucleotide polymorphisms (SNPs); the remaining ones showed nonsynonymous variations. The expression of <i>HvPLATZ2/3/8</i> was ubiquitous in various tissues, whereas <i>HvPLATZ7</i> appeared transcriptionally silent; the remaining genes displayed tissue-specific expression. The expression of <i>HvPLATZs</i> was modulated by salt stress, potassium deficiency, and osmotic stress, with response patterns being time-, tissue-, and stress type-dependent. The heterologous expression of <i>HvPLATZ3/5/6/8/9/10/11</i> in yeast enhanced tolerance to salt and osmotic stress, whereas the expression of <i>HvPLATZ2</i> compromised tolerance. These results advance our comprehension and facilitate further functional characterization of <i>HvPLATZs</i>.